“I have successfully privatized world peace,” Tony Stark (Robert Downey Jr.) crows in front of the Senate Armed Services Committee at the beginning of Iron Man 2. Life has been treating our hero pretty well since Iron Man, with the super-suited billionaire playboy basically stabilizing the world and becoming an even bigger international megacelebrity between the first film and this sequel. Of course, pride and falls being what they are, there’s little doubt what’s coming his way next.

Iron Man 2’s villain-cum-career-crises arrive in the form of the hulking and sinister Ivan Vanko (Mickey Rourke), the aptly named Whiplash. Vanko has family beef he’s been waiting to settle with the Stark clan, so he mobs up with Tony’s arms-industry rival Justin Hammer (a sublimely goofy and show-stealing Sam Rockwell) in order to do a little Marvel-style problem-solving: constructing his own Arc Reactor-powered suit so he can go toe-to-toe with Iron Man.

If you were expecting a meditation on the perils and pitfalls of the military-industrial complex and war-as-business, you’re going to have to be content with some very muted undertones. No, this is a movie about CG explosions first and foremost, except for the protracted scenes where nothing much happens and Iron Man finds himself lounging in a giant fake donut on an ennui-fueled bender.

Downey puts in another solid turn as the quip-filled Tony Stark, minus some of the bravado that gave him almost Cary Grant levels of devil-may-care swagger in the first movie. And Don Cheadle does a serviceable job replacing Terrence Howard as Col. Rhodes, giving the film ample opportunity for knowing winks at buddy-flick cheese after Rhodes suits up as War Machine, Iron Man’s sidekick/partner.

But for all of its star-power and CGI wizardry (some of the action scenes seem perfectly calibrated to tickle your superfan receptors), Iron Man 2 can’t quite manage the balance between plot development and action. Just as you think there’s about to be some payoff for yet another overlong sequence spent plumbing Stark’s family history, or watching Vanko pace like a caged animal and generally devour scenery, the movie abruptly shifts gears and tosses in another joyless chase sequence or string of explosions.

It’s a shame that director Jon Favreau didn’t trust his actors more; where the first Iron Man was a character-driven delight—something of a thinking-man’s blockbuster—the sequel succumbs to, well, sequel-itis, opting instead to crank up the special effects and noise and hope for the best. The most cynical and calculating part of it all is that the movie never really finds a justification for its existence; except, that is, as a bald-faced setup for The Avengers.